Under certain operating conditions aircraft are vulnerable to accumulation of ice on component surfaces. It is well known that such accumulation of ice can lead to disastrous results. A wide variety of systems have been developed for removing ice from aircraft during flight and can be placed into three general categories: thermal, chemical, and mechanical.
The mechanical category of deicing systems operate by distorting the airfoil surface of the aircraft to be deiced. Distortion of the airfoil surface causes cracking in the ice accumulated thereon, and subsequent dispersal of that ice into the air stream passing over the aircraft component.
The principal commercial mechanical deicing means is commonly referred to as pneumatic deicing wherein a component (e.g. the leading edge of a wing) of an aircraft is covered with a plurality of expandable, generally tube-like structures inflatable by employing a pressurized fluid, typically air. Upon inflation, the tubular structures tend to expand substantially the leading edge profile of the wing or strut and crack ice accumulating thereon for dispersal into the air stream passing over the aircraft component. Typically, such tube-like structures have been configured to extend substantially parallel to the leading edge of the aircraft component.
FIG. 1 illustrates a prior pneumatic deicer 12 formed from an elastomeric composite having rubbery or substantially elastic properties. The deicer 12 is disposed on an airfoil 14. A plurality of tubes 16 are formed in the composite and are provided pressurized fluid, such as air, from a manifold 18. The manifold 18 is supplied fluid via a connector,20, which transfers fluid from a pressurized source (not shown). Connector 20 is integrated into the deicer 12 during manufacturing. Tubes 16 expand or stretch under pressure by 40% or more during inflation cycles, thereby causing a substantial change in the profile of the deicer (as well as the leading edge) to cause cracking of ice accumulating thereon.
Referring now to FIG. 2, a prior pneumatic deicing system 10 is comprised of a deicer 12 having a plurality of tubes 16 and a manifold 18 provided therein. The deicer 12 is bonded or attached to an airfoil 14. Pressurized fluid is provided to manifold 18 via a connector 20, which is integrated into deicer 12. A large hole 22 must be provided in airfoil 14 in order to accommodate connector 20. One drawback to the system illustrated in FIGS. 1 and 2 is that hole 22 provides a significant source of radar reflection when so exposed. Another drawback to this deicing system is that connector 20 represents a size limitation in that the thickness of the airfoil 14 cannot be smaller than the smallest manufacturable height of connector 20. In other words, connector 20 imposes a size restriction on the airfoil because the connector can be reduced in size only so much. The deicer system cannot be utilized therefore, for very thin airfoils, such as propellers of an airplane or the rotor of a helicopter. Efforts to improve such pneumatic deicing systems have led to continuing developments to improve their versatility, practicality and efficiency.